Defect inspection device, pattern chip, and defect inspection method

ABSTRACT

In a defect inspection device that irradiates a surface of a sample or a surface of a pattern chip with an illumination light shaped to extend in a first direction, and detects a scattered light generated from the surface of the sample or the surface of the pattern chip by the illumination light to detect a defect on the surface of the sample, the pattern chip has a dot pattern area in which multiple dots are arrayed in multiple rows and multiple columns, a minimum interval between the dots corresponding to the lines aligned in the first direction among the multiple dots arrayed in the dot pattern area in a second direction orthogonal to the first direction is smaller than a width of the illumination light, and a minimum interval between the multiple dots arrayed in the dot pattern area is larger than a resolution of the detection optical system.

TECHNICAL FIELD

The present invention relates to a defect inspection device thatinspects a defect generated in a pattern of an object, a pattern chipused in the device, and a defect inspection method executed in thedevice.

BACKGROUND ART

For example, a semiconductor device, a liquid crystal display element,and a printed circuit; board are manufactured by forming a pattern on asubstrate. In a manufacturing process for the semiconductor device, theliquid crystal display element, and the printed circuit board, in orderto inspect a defect occurring at the time of forming the pattern andtake countermeasures against the defect, a defect inspection device thatdetects a defect occurrence condition is used.

The defect inspection device of this type is disclosed in PatentLiterature 1. Patent Literature discloses “a defect inspection devicefor inspecting a sample, including a table unit, an illumination lightirradiation unit, a detection optical system unit, and a signalprocessing unit in which the table unit is movable and allows a sampleto be inspected and a pattern chip to be placed on the table unit, theillumination light irradiation unit irradiates a surface of the sampleplaced on the table unit or a surface of the pattern chip with anirradiation light linearly formed, the detection optical system unitincludes a plurality of detection optical systems each having anobjective lens and an image sensor and placed at a plurality oflocations above the table unit, and forms on the image sensors anddetects images caused by scattered lights incident to the respectiveobjective lenses of the plurality of detection optical systems placed atthe plurality of locations, among scattered lights generated from thesample irradiated with the linearly formed illumination light by theillumination light irradiation unit, and the signal processing unitprocesses signals detected by the plurality of detection optical systemsof the detection optical system unit to detect a defect of the simplesurface, wherein a plurality of repetitive patterns for generating thescattered lights corresponding to positions of the respective objectivelenses of the multiple detection optical systems in the detectionoptical system unit when the linearly formed illumination light isirradiated by the illumination light irradiation unit is periodicallyformed in the pattern chip”(claim 1 of scope of claims).

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Unexamined Patent Application    Publication No. 2014-174052

SUMMARY OF INVENTION Technical Problem

Patent Literature 1 discloses a defect inspection device capable ofstably matching a focal point of illumination light and a focal point ofmultiple detection systems within respective focal depths. A patternchip disclosed in Patent Literature 1 has a pattern corresponding to adetection system in an oblique direction, and the pattern is a line andspace pattern which is not orthogonal to a longitudinal direction of anillumination beam which is elongated in one direction. Therefore, anarea having a finite width where an illumination area of a linearillumination light having a certain width overlaps with the line andspace pattern is detected as an image in a detection system in anoblique direction. For that reason, in the adjustment of a focalposition of the detection system in the oblique direction, since aspread of the image having the finite width due to defocus and a changein peak strength are measured, a change in the image when the amount ofdefocus is small was small, resulting in a problem that the focalposition could not be adjusted with high precision.

Therefore, it is an object of the present invention to provide atechnique in which an optical system including an illumination opticalsystem that irradiates a linear illumination light and multipledetection optical systems which detect a scattered light except for aspecularly reflected light from a sample can be adjusted with highprecision.

Solution to Problem

In order to solve the problem described above, the present inventionemploys, for example, configurations defined in claims. The presentspecification includes multiple solution to the problem, and an exampleof the solutions is directed to “In a defect inspection device thatirradiates a surface of a sample or a surface of a pattern chip with anillumination light shaped to extend in a first direction, and detects ascattered light generated from the surface of the sample or the surfaceof the pattern chip by the illumination light to detect a defect on thesurface of the sample, the pattern chip has a dot pattern area in whichmultiple dots are arrayed in multiple rows and multiple columns, aminimum interval (dx) between the dots corresponding to the linesaligned in the first direction among the multiple dots arrayed in thedot pattern area in a second direction orthogonal to the first directionis smaller than a width of the illumination light, and a minimuminterval (d) between the multiple dots arrayed in the dot pattern areais larger than a resolution of the detection optical system.

Advantageous Effects of Invention

According to the present invention, the optical system including theillumination optical system that irradiates the linear illuminationlight and the multiple detection optical systems that detect thescattered light except for the specularly reflected light from thespecimen can be adjusted with high accuracy, and a stable defectinspection can be realized with high sensitivity. Other problems,configurations and advantages other than those described above will beclarified by the following description of the embodiments.

BRIEF DESCRIPTION OF EMBODIMENTS

FIG. 1 is a diagram showing a schematic configuration of a defectinspection device according to a first embodiment.

FIG. 2 is a side view showing a detailed configuration of anillumination optical system and a vertical detection optical systemaccording to the first embodiment.

FIG. 3 is a side view showing a configuration and a placement of adetection optical system according to a first embodiment.

FIG. 4 is a perspective view showing a positional relationship betweenan incident direction of an oblique illumination on an inspection targetsubstrate arid detection directions of multiple detection opticalsystems.

FIG. 5 is a plan view showing a configuration example of a pattern chipused in the first embodiment.

FIG. 6 is a plan view showing a configuration example of a dotsingle-row pattern area used in the first embodiment.

FIG. 7 is a diagram showing a color map of a scattered lightdistribution calculation result by dots of the pattern chip used in thefirst embodiment and an opening position of the detection opticalsystem.

FIG. 8 is a plan view showing a configuration example of a dot patternarea used in the first embodiment.

FIG. 9 is a diagram showing a waveform of a detection signal obtainedfrom a dot pattern area of the pattern chip according to the firstembodiment.

FIG. 10 is a flowchart showing an adjustment procedure of an opticalsystem using the pattern chip according to the first embodiment.

FIG. 11 is a flowchart showing an inspection procedure includingadjustment of the optical system by the defect inspection deviceaccording to the first embodiment.

FIG. 12 is a plan view showing a configuration example of a dot patternarea used in a second embodiment.

FIG. 13 is a plan view showing a configuration example of a dot patternarea used in a third embodiment.

FIG. 14 is a schematic diagram showing a relationship between adiffracted light distribution by the doc pattern area used in the thirdembodiment and an opening position of a detection optical system.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings. The embodiments of the presentinvention are not limited to embodiments described later, and variousmodifications are enabled within a scope of the technical idea of theembodiments.

(1) First Embodiment

FIG. 1 show's a configuration example of a defect inspection device 1000according to the present embodiment. The defect inspection device 1000includes a light source unit 101, a TTL illumination optical system 111,an oblique illumination optical system 112, an objective lens 102, anobjective pupil optical unit 103, a polarizer 104, an imaging lens 105,a detector 106, a signal processing unit 200, an overall control unit301, a display unit 302, an arithmetic unit 303, a storage unit 304, astage drive unit 151, an X-Y-Z-θ stage 152 (.hereinafter referred to as“stage 152”), and a pattern chip 191.

An illumination light emitted from the light source unit 101 isreflected by a mirror 110 and an optical path of the reflectedillumination light is bent toward a mirror 113. The illumination lightincident on the mirror 113 is further reflected and incident on theoblique illumination optical system 112. The oblique illuminationoptical system 112 linearly condenses the incident illumination light.An inspection target substrate 2 is irradiated with thelinearly-condensed illumination light from obliquely above theinspection target substrate 2. In this example, the mirror 110 can enterand exit the optical path of the illumination light emitted from thelight source unit 101. When the mirror 110 is moved to a positiondeviated from the optical path of the illumination light, theillumination light enters the TTL illumination optical system ill. Theillumination light incident on the TTL illumination optical system 111is linearly-condensed and enters the objective pupil optical unit 103and an optical path of the illumination light is bent in a direction ofthe objective lens 102. The inspection target substrate 2 is irradiatedwith the illumination light having passed through the objective lens 102from a normal direction of the inspection target substrate 2.

A specularly reflected light, a diffracted light, and a scattered light(hereinafter those lights are collectively referred to as “reflectedlight”) are generated by irradiating the inspection target substrate 2with an oblique illumination light having passed through the obliqueillumination optical system 112 or a vertical illumination light havingpassed through the TTL illumination optical system 111. After thespecularly reflected light, the diffracted light, and the scatteredlight have entered the objective lens 102 and have been condensed, thoselights are imaged on a detection surface of the detector 106 through theobjective pupil optical section 103, the polarizer 104, and the imaginglens 105 in order and converted into an electric signal. It should benoted that the polarizer 104 may be disposed between the imaging lens105 and the detector 106 and immediately before the detector 106. Inaddition, the polarizer 104 has a rotation mechanism and a mechanismthat retreats to the outside of an optical axis. The rotation mechanismcan set the polarizer 104 to an arbitrary light inspection angle. Theretreating mechanism can switch the polarizer 104 between use andnonuse.

An electric signal output from the detector 106 is input to the signalprocessing unit 200. The signal processing unit 200 is basicallyconfigured by a computer. In other words, the signal processing unit 200includes an input/output device, a storage device, a control device, anarithmetic device, and so on. The signal processing unit 200discriminates whether a defect is present or not, by comparing anelectric signal corresponding to an inspection area with an electricsignal obtained from another area on the inspection target substrate 2,and outputs information on the detected defect. The feature amount andposition information of the defect including a signal intensity of thedefect detected by the signal processing unit 200 are stored in thestorage unit 304 through the overall control unit 301 and also displayedon the display unit 302. The inspection target substrate 2 is scanned bythe stage 152 driven by the stage drive unit 151 and an entire surfaceof the inspection target substrate 2 is inspected.

In FIG. 1, only one detection optical system (configured by theobjective lens 102, the objective pupil optical unit 103, the imaginglens 105, and the detector 106) of the defect inspection device 1000 isillustrated, but actually, multiple detection optical systems areinstalled so that the objective lenses 102 do not mechanically.interfere with each other. In the drawing, reference symbol “a”indicates that the objective lens 102, the objective pupil optical unit103, the imaging lens 105, and the detector 106 belong to the detectionoptical system of some system. Therefore, the signal processing unit 200actually processes the multiple electric signals detected through themultiple detection optical systems to determine a defect.

A temperature gauge 2002 and a barometer 2003 for monitoring atemperature and a pressure are installed in a device internal space 2001in which an illumination optical system and a detection optical systemare installed and a measured value of an environmental condition in thedevice internal space 2001 is always transmitted to the overall controlunit 301.

FIG. 2 shows a more detailed configuration of the illumination opticalsystem and the detection optical system. The light source unit 101includes a laser light source 1011, an attenuator 1012, an ND filter1013, a wavelength plate 10.14, and a beam expander 1015. An output of alaser oscillated and output from the laser light source 1011 is adjustedby the attenuator 1012, the light amount of laser is adjusted by the NDfilter 1013, a polarization state of the laser is adjusted by thewavelength plate 1014, and a beam diameter and a shape of the laser areadjusted and controlled by the beam expander 1015. Then, the laser isemitted as an illumination light.

An optical path of the illumination light emitted from the light sourceunit 101 is guided to the TTL illumination optical system 111 or theoblique illumination optical system 112 depending on whether the mirror110 is present or not. In other words, when the mirror 110 that has beenmoved by a drive device not shown is installed at a position deviatingfrom an optical path of the illumination light, the illumination lightemitted from the light source unit 101 enters the TTL illuminationoptical system 111 through the mirror unit 1102. On the other hand, inthe case where the mirror 110 that has been moved by the drive devicenot shown is installed on the optical path of the illumination light,the illumination light emitted from the light source unit 101 isreflected by the mirror 110, is incident on the mirror unit 1101,further reflected by the mirror unit 1101, and enters the obliqueillumination optical system 112. The illumination light incident on theTTL illumination optical system 111 or the oblique illumination opticalsystem 112 is shaped into a light beam that is elongated in onedirection and then emitted from the TTL illumination optical system 111or the oblique illumination optical system 112.

A short wavelength, a high output, a high luminance and a high stabilityare suitable for the laser light source 1011, and the laser light source1011 using the third, fourth, or fifth harmonic of a YAG laser(respective wavelengths are 355, 266, and 213 nm) or the like isemployed. An angle and a position of the illumination light incident onthe oblique illumination optical system 112 or the TTL illuminationoptical system 111 are controlled by the mirror unit 1101 or 1102,respectively, and are adjusted so that the inspection target substrate 2is irradiated with the illumination light illuminated at a desiredposition. The mirror units 1101 and 1102 are each configured by multipleplane mirrors, and the angle and the position of the illumination lightare adjusted by adjusting the angle and the position of the planemirror.

FIG. 3 shows a placement relationship of the multiple detection opticalsystems. A vertical detection optical system 170 a includes an objectivelens 102 a, a polarizer 104 a, an imaging lens 105 a, and a detector 106a. The vertical detection optical system 170 a forms an image caused bya reflected light condensed by the objective lens 102 a after generatedfrom the inspection target substrate 2 on the detector 106 a, to therebydetect the reflected light. A left oblique detection optical system 170b includes an objective lens 102 b, a polarizer 104 b, an imaging lens105 b, and a detector 106 b. The left oblique detection optical system170 b forms an image caused by a reflected light condensed by theobjective lens 102 b after generated from the inspection targetsubstrate 2 on the detector 106 b, to thereby detect the reflectedlight. A right oblique detection optical system 170 c includes anobjective lens 102 c, a polarizer 104 c, an imaging lens 105 c, and adetector 106 c. The right oblique detection optical system 170 c formsan image caused by a reflected light condensed by the objective lens 102c after generated from the inspection target substrate 2 on the detector106 c, to thereby detect the reflected light.

The vertical detection optical system 170 a includes an objective pupiloptical unit 103 and guides the vertical illumination light to theinspection target substrate 2. The vertical detection optical system 170a further includes a mirror 108 inser table into and retractable fromthe optical path and a two-dimensional detector 109 which is at aconjugate position with the detector 106 a. The two-dimensional detector109 can detect a two-dimensional image which is substantially the sameimage plane as that of the detector 106 a. The mirror 103 is a halfmirror or a total reflection mirror. When the half mirror is used,signals from the detector 106 a and the two-dimensional detector 109 canbe detected at the same time.

The detectors 106 a, 106 b, and 106 c are held by stages 107 a, 107 b,and 107 c, respectively. The detectors 106 a, 106 b, and 106 c areconfigured by CCD linear image sensors, CMOS linear image sensors, orthe like. The stages 107 a, 107 b, and 107 c each have translationmechanisms of X, Y and Z and a biaxial rotation mechanism, and adjustthe position and posture (azimuth angle, tilt angle) of the detector bythose mechanisms. The adjustment is performed so that an azimuthdirection and an image plane of the image formed in an illumination areaR_(I) to be described later by the respective detection optical systemsin a longitudinal direction coincide with an azimuth direction and alight receiving surface of the detectors 106 a, 106 b, and 106 c in thelongitudinal direction. The azimuth angle is a rotation angle in a planeperpendicular to the optical axis of each detection optical system, andthe tile angle is an inclination angle to a plane perpendicular to theoptical axis.

FIG. 4 shows a relationship between an irradiation direction of theoblique illumination light to the inspection target substrate 2 and adetection direction (detection opening position) of the detectionoptical system. It is assumed that an incident direction of the obliqueillumination light output by the oblique illumination optical system 112on the inspection target substrate 2 is L_(I) and a reflection directionof the oblique illumination light by the inspection target substrate 2is L_(R). It is assumed that an illumination area on the inspectiontarget substrate 2 which is irradiated with the oblique illuminationlight or the vertical illumination light is R_(I). An opening (an areain a direction of the reflected light condensed by the objective lens102 a in the reflected light from the inspection target substrate 2) isrepresented by 102A, an opening of the left oblique detection opticalsystem 170 b is represented by 102B, and an opening of the right obliquedetection optical system 170 c is represented by 102C.

When an XYZ coordinate system is set such that L_(I) and L_(R) arepresent in a YZ plane, a center of the opening 102A is in a Z axisdirection. At that time, the centers of the openings 102 B and 102 C arepresent in an XZ plane and placed in a direction inclined by θ_(D) fromthe Z axis. The oblique illumination optical system 112 and the TTLillumination optical system 111 form a linear illumination beam(irradiation area R_(I)) parallel to the Y axis on the inspection targetsubstrate 2. With the above placement, the specularly reflected light(L_(R)) of the oblique illumination light does not enter the detectionoptical system (170 a, 170 b, 170 c). In addition, since the opticalaxis of each of the detection optical systems (170 a, 170 b, 170 c) isorthogonal to the longitudinal direction of the illumination area R_(I),the image can be focused over the entire area of the illumination areaR_(I). Since the detection optical systems (170 a, 170 b, 170 c) do notdetect the specularly reflected light but detect only the diffractedlight and the scattered light, a flat area on the inspection targetsubstrate 2 becomes a dark state, and only an uneven shape (circuitpattern, foreign matter, or the like) emitting the diffracted light orthe scattered light is detected. As a result, the defect inspection canbe performed with high sensitivity. Further, the image is focused overthe entire area of the illumination area R_(I), as a result of which aclear image without blur is obtained over the entire area of theillumination area R_(I). Therefore, the defect inspection can beperformed with high speed and high sensitivity.

An AF illumination beam emitted from an autofocus (AF: autofocus)illumination system 181 is reflected by the inspection target substrate2 through an optical path L_(AI) and received by an AF light receivingsystem 182 through an optical path L_(AR). The AF illumination system181 has a light source and a projection lens and projects a slit-shapedimage onto the inspection target substrate 2. The AF light receivingsystem 182 has a light receiving lens and a position sensitive element(PSD: position sensitive detector) and measures a position of the slitimage. The AF light receiving system 182 measures a displacement of theslit image due to a vertical movement of the inspection target substrate2 to measure the vertical movement of the inspection target substrate 2.A measurement signal is input to the overall control unit 301 and thestage drive unit 151 and used for adjustment of the illumination opticalsystem and detection optical system of the defect inspection device1000, and adjustment of a height (Z) of the inspection target substrate2 by the stage 152.

Instead of the AF illumination system 181 and the AF light receivingsystem 182, an AF illumination and light receiving system having a lightsource, a projection lens, a light receiving lens, and a positiondetection element is disposed at a position of the AF illuminationsystem 181. A reflection mirror is disposed at a position of the AFlight receiving system 182. An AF illumination beam emitted by the AFillumination and light receiving system is reflected by the reflectionmirror, and again received the AF illumination and light receivingsystem to measure a variation in the slit image during reciprocation,thereby being capable of measuring a height of the inspection targetsubstrate 2 with higher precision.

In the case of the placement of the illumination optical system and thedetection optical system, unless a concavo-convex pattern is present inthe illumination area R_(I), a signal caused by the illumination lightcannot be detected in the detection optical system, and the illuminationoptical system and the detection optical system can be adjusted based onthe signal. On the other hand, if a sample having the concavo-convexpattern is placed at substantially the same position as that of theinspection target substrate 2 and a detection signal derived from thesample is measured, the diffracted light and the scattered lightgenerated from the illumination area R_(I) can be detected by thedetection optical system and the illumination optical system so that thedetection optical system can be adjusted. A structure having theconcavo-convex pattern is the pattern chip 191.

FIG. 5 shows a configuration example of the pattern chip 191. Theillumination optical system and the detection optical system areadjusted with the use of the concave and convex pattern of the patternchip 191, as a result of which the illumination optical system and thedetection optical system can be adjusted under the same conditionirrespective of the pattern of the inspection target substrate 2, andthe optical system can be kept in a stable state for a long period oftime.

In order to adjust the optical system under the condition close to acondition at the time of inspecting the inspection target substrate 2,it is desirable that the pattern chip 191 is installed in the vicinityof the inspection target substrate 2 so that a height of a surface ofthe pattern chip 191 is substantially equal to that of the inspectiontarget substrate 2. When the surface height of the inspection targetsubstrate 2 is different from the surface height of the pattern chip191, a height Z of the stage 152 is corrected with the use of adifference in height between the surfaces of the inspection targetsubstrate 2 and the pattern chip 191 so that the height of the detectiontarget pattern is set to be substantially equal between at the time ofthe adjustment using the pattern chip 191 and at the time of inspectionof the inspection target substrate 2.

The pattern chip 191 has a concavo-convex pattern for generating thediffracted light and the scattered light in a pattern area 601 of thesurface. In FIG. 5, a longitudinal direction of the linearly shapedillumination area R_(I) is defined as a Y direction, and a widthdirection (direction orthogonal to the longitudinal direction) of theillumination area R_(I) is defined as an X direction. The pattern area601 has multiple small pattern areas 602 a, 602 b, 602 c, and so onaligned in the Y direction.

Area sizes of the small pattern areas 602 a, 602 b, 602 c, and so on andpatterns formed in those small pattern areas are common to each other.Hereinafter, those small pattern areas 602 a, 602 b, 602 c, and so onare collectively referred to as “small pattern areas 602”. A length ofthe small pattern area 602 in the Y direction is shorter than a lengthof the illumination area R_(I) in the Y direction (for example, 1/4 orless). Therefore, the multiple small pattern areas 602 are includedwithin a range of the illumination area R_(I) in the Y direction. Forexample, four or more small pattern areas 602 are included in theillumination area R_(I). As a result, in the small pattern areas 602(four or more areas) of the illumination area R_(I) in the Y direction,the adjustment of the illumination optical system and the detectionoptical system to be described later can be carried out with the use ofthe common pattern. This makes it possible to reduce a variation in anadjustment state depending on a position in the Y direction within theillumination area R_(I) (that is, the position within a detection visualfield) and reduce a variation in sensitivity.

Each of the small pattern areas 602 includes a dot one-row pattern area611, a line and space (hereinafter referred to as “L & S”) pattern area612, and a dot pattern area 613.

In FIGS. 4 and 5, the illumination area R_(I) is shown as an ellipse forthe sake of convenience. Actually, the illumination area RI has anelliptical Gaussian distribution in which an intensity distribution ofthe illumination light is elongated in the Y direction, and an area inwhich a relative intensity relative to a distribution center is 1/e² ormore corresponds to the illumination area R.. A width of theillumination area R_(I) is a light condensing width of the Gaussiandistribution condensed in the X direction and with the use of the linearillumination light in the illumination area R_(I) which is narrow andthin, a detection resolution and an illumination power density in the Xdirection can be enhanced, thereby being capable of realizing a defectinspection with high sensitivity. A width of the illumination area R_(I)in the X direction ranges from 0.5 μm to 1.5 μm. The narrower width isadvantageous to higher sensitivity, but there is a need to increase anaperture angle for condensing the illumination, which makes it difficultto keep the stability of the inspection because the depth of focusbecomes narrow. In practical use, the width is appropriately about 0.8μm.

FIG. 6 shows a configuration example of the dot one-row pattern area611. The dot one-row pattern area 611 is obtained by aligning the samedot pattern as that in the L & S pattern area 612 in a straight line atpredetermined intervals in the X direction, Each black circlecorresponds to a dot 1903. Intervals of the dots 1903 within the dotone-row pattern area 611 in the X direction are smaller than a width ofthe illumination area R_(I) and a pixel dimension of the detectors 106a, 106 b, and 106 c in the X-direction. For that reason, regardless of arelative position of the illumination area R_(I) with respect to the dotrow in the X direction, a signal derived from any dot is detected tomeasure a detection position of the dot row in the Y direction by eachof the detectors 106 a, 106 b, and 106 c.

The scattered light of the dot pattern in the dot one-row pattern area611 appears almost, evenly in all directions as shown in FIG. 7.Therefore, the scattered light can be detected by all of the detectionoptical systems (170 a, 170 b, and 170 c). In the detectors 106 a, 106b, and I06 c, intervals of the signals in the Y direction of the pluraldot one-row pattern areas 611 arrayed in the Y direction areproportional to magnifications of the respective detection opticalsystems. For that reason, the magnifications of the respective detectionoptical systems can be adjusted to desired values with reference to thedetected intervals of the dot one-row pattern area 611 in the Ydirection.

Further, the positions of the signals of the dot one-row pattern area611 in the Y direction in the detectors 106 a, 106 b, and 106 c aremeasured, and combined together among the multiple detectors, therebybeing capable of combining the positions (Y-direction positions of thedetection target areas on the pattern chip 191) of the detectors 106 a,106 b, and 106 c in the Y direction together. As a result, the signalsobtained by detecting the same location on the inspection targetsubstrate 2 by the detectors 106 a, 106 b, and 106 c can be subjected tocomparison and integration processing, thereby being capable ofimproving the inspection sensitivity.

The L & S pattern area 612 is configured by multiple line patterns whichare aligned at predetermined pitches in the Y direction and areelongated in the X direction. When the line pattern in the X directionis irradiated with the oblique illumination light or the verticalillumination light, the intense diffracted light and scattered light aregenerated in the XZ plane. Since the signal in the L & S pattern area612 is strongly detected by the vertical detection optical system 170 a,the signal is used for the adjustment of the vertical detection opticalsystem 170 a and the adjustment of the obiique illumination opticalsystem 112 and the TT1 illumination optical system 111 based on thesignal detected by the vertical detection optical system 170 a.

On the other hand, the signal of the L & S pattern area 612 is weak inthe oblique detection optical system (170 b, 170 c). For that reason,the adjustment of the oblique detection optical system (170 b, 170 c) isperformed with the use of the signals of the dot one-row pattern area611 and the dot pattern area 613.

FIG. 3 shows an example of the configuration of the dot pattern area613. Black circles in the figure correspond to the individual dots 1903.The dot pattern area 613 is configured such that a minimum repetitionunit area 1902 is repetitively arrayed in two dimensions (X directionand Y direction). The minimum repetition unit area 1902 is an elongatedarea in the Y direction. The multiple dots in the area are disposedlinearly so as to be mirror symmetric with respect to a center positionin the Y direction. The configuration in which the minimum repetitionunit areas 1902 are aligned only in the X direction is drawn in FIG. 8for the limitation of a paper space. In this way, the minimum repetitionunit area 1902 is a repetition basic unit.

In this example, a minimum interval of the dots 1903 in the X directionin the minimum repetition unit area 1902 is defined as dx and aninterval in the Y direction is defined as dy. As shown in FIG. 8, dxcorresponds to a minimum interval of the multiple dots in the Xdirection, which correspond to each of the rows aligned in the Ydirection. In addition, a length of the minimum repetition unit area1902 in the X direction is defined as 1x and a length in the Y directionis defined as 1 y .

A size of the dot pattern area 613 is M×N times the minimum repetitionunit area 1902. M is the number in the X direction and N is the numberin the Y direction. As usual, M is about 2,000 to 10,000 and N is about5 to 50. An example of preferable parameters is dx=0.1 μm, dy=1 μm, and(M, N)=(5000, 10). In that case, a size of the minimum repetition unitarea 1902 is 1x×1 y=1 μm×20 μm (X direction×Y direction), and a size ofthe dot pattern area 613 is 5 mm×200 μm.

The dot pattern area 613 increases more in the X direction as the numberof repetitions M in the X direction is larger, and the fine adjustmentof the position of the illumination area R_(I) in the X directionbecomes unnecessary. In particular, when the pattern chip 191 isirradiated with the illumination light in an ultraviolet area which isshort in a wavelength, the pattern formed on the pattern chip 191 isdeteriorated by being damaged by irradiation with the illuminationlight. The deterioration changes the intensity and distribution of thescattered light generated from the pattern, as a result of which anadjustment state of the optical system adjustment, using the patternchip 191 is changed. Thus, irradiation with the illumination light inthe ultraviolet area suffers from a problem of impairing the stabilityof the inspection performance.

On the other hand, in the present embodiment, the dot pattern area 613is elongated in the X direction and a large number of the same patterns(that is, the minimum repetition unit area 1902) are present in the Xdirection. For that reason, in the case of the pattern chip 191according to the present embodiment, an installation position of thepattern chip 191 is merely displaced in the X direction relative to thelinear illumination area Rx, thereby being capable of executing the sameadjustment operation as that before displacement. Therefore, theinstallation position of the pattern chip 191 is displaced periodicallyin the X direction, thereby being capable of preventing the pattern chip191 from being damaged by irradiation of the illumination light in theultraviolet area for a long period of time. Alternatively, another areaof the pattern chip 191 which is not deteriorated is used without theuse of the deteriorated area on the pattern chip 191, thereby beingcapable of executing the stable adjustment for a long period of time.

A width Ix of the minimum repetition unit area 1902 in the X directionis larger than a width of the illumination area R_(I) in the X direction(for example, 0.8 μm). In addition, only one dot 1903 is present in thesame Y coordinate within the minimum repetition unit area 1902. Thoseconditions make it possible to prevent the overlapping signals of themultiple dots from being detected when detecting the dot pattern area613 by the linear image sensors (detector 106 a, 106 b, and 106 c)elongated in the Y direction.

The individual dots 1903 are configured by substantially circularconcave or convex patterns patterned on a silicon substrate by focusedion beam processing, electron beam processing, laser processing,photolithography, or the like, a substantially circular opaque patternformed on a transparent substrate such as synthetic quartz, or the like.

The scattered light is generated from the dot 1903 by the illuminationlight from the oblique illumination optical system and is detected bythe detection optical system. A diameter of the circular pattern mayfall within a range of 0.05 μm to 0.2 μm, and preferably, example, 0.1μm. For example, when the wavelength of the illumination light is 266nm, since a circular pattern with a diameter of 0.1 μm is sufficientlysmaller than the illumination wavelength, the circular pattern isdetected as an image similar to a point pattern having substantially nolength.

In the case where a processing device used for processing the patterndoes not correspond to the processing of the circular pattern, a regularquadrangle or a regular hexagon having the same size as that of thecircular pattern, a shape approximated to a circle by combining minutetriangles or quadrangles together, or the like can be substituted forthe circular pattern. If a difference between those substitute shapesand the ideal circular pattern is smaller than the wavelength of theillumination light, a spatial resolution at the time of detection, or aprocessing resolution of the processing device, the substitute shapepatterns function in the same manner as that of the circular pattern.

Returning to the description of FIG. 7, as described above, FIG. 7 showsan angular distribution of the scattered light by the dot pattern Agreat circle in FIG. 7 indicates that; the illumination direction shownin FIG. 4 and the opening position of the detection optical system areplaced on a celestial sphere centered on an origin of the X, Y, and Zaxes shown in FIG. 4. Further, a hemisphere having Z of 0 or more isprojected on the XY plane and displayed. FIG. 7 shows the respectivepositions of a tip of the vector L_(R) indicating the specularlyreflected light direction of the oblique illumination light and theopenings 102A, 102B, and 102C of the detection optical system. FIG. 7shows the angular distribution (calculated value by simulation) of thescattered light intensities of the cylindrical concave dot pattern witha diameter of 0.1 μm and a depth of 0.1 μm. The illumination is anoblique illumination with a wavelength of 266 nm and S- and P-polarizedlights.

In order to detect the scattered light of the dot pattern by eachdetection optical system and perform the adjustment, it is desirablethat the openings 102A, 102B, and 102C of the detection optical systemare distributed widely over the entire area so as to obtain sufficientdetection signal intensity. In addition, in order to detect and measurethe defocus of the detection optical system with high accuracy, it isdesirable that the distribution of the scattered light uniformly spreadsinside the openings 102A, 102B, and 102C of the individual detectionoptical systems as compared with the case in which the distribution ofthe scattered light is locally biased in the openings 102A, 102B, and102C. The distribution of the scattered light shown in FIG. 7 satisfiesthose conditions. The distribution of the scattered light of the dotpattern is distributed almost uniformly on the celestial sphere becausethe size of the dot; pattern is shorter than the wavelength andscattering which can be approximated by Rayleigh scattering occurs.

In the polarized light of illumination light, the P-polarized light hasa larger scattered light intensity than that of the S-polarized light.For that reason, it is preferable to use the P-polarized light when thedot pattern is irradiated with the oblique illumination light to performthe adjustment. In consideration of the convex pattern of the samecylindrical shape, it is known that the P-polarized illumination has alarger scattering intensity than that of the S-polarized light, but thescattered light intensity is biased around the specular reflection (LR).On the other hand, in the case of the concave pattern, as shown in FIG.7, in the P-polarized illumination larger in the scattered lightintensity, the scattered light spreads evenly around the position of theopening 102A. For that reason, the concave pattern is more preferablethan the convex pattern.

FIG. 9 shows the waveform of the detection signal obtained when the dotpattern area 613 is irradiated with the vertical illumination light orthe oblique illumination light, and the dot pattern area 613 is detectedby the detection optical system (170 a, 170 b, or 170 c). In FIG. 8, letus consider a situation (adjustment state 1 in FIG. 9) in which thecenter position of the illumination area in the width direction (Xdirection) is in the vicinity of X=5 dx. As described above, when thewidth of the illumination area R_(I) in the X direction is 0.8 μm,dx=0.1 μm, dy=1 μm, and 1 y=20 μm, since the signal of the dot patternto be detected is proportional to the illumination intensity at theposition of the dot, the signal intensity of the dots 1903 of Y=5 dy and15 dy close to the center of the illumination area R_(I) is largest. Ifthe center of the illumination area R_(I) is located at X=4 dx(adjustment state 2 in FIG. 9), the dots 1903 of Y=4 dy and 16 dyapproach the center of the R_(I), and those dot signal intensities aremaximal. Conversely speaking, if the signal of the portion with thelargest signal corresponds to the signal of the dot 1903 closest to thecenter of the illumination area R_(I) in the X direction.

In the present embodiment, since the dot interval dx in the X directionis 0.1 μm and is sufficiently smaller than the width of the illuminationarea R_(I) in the X direction, almost equivalent signal intensity(maximum value) can be measured for all of the dots located in thecenter of the illumination area R_(I).

In the present embodiment, the interval dy of the dots in the Ydirection is 1 μm and the interval d between the closest dots is 1.005μm, and since both of those intervals is larger than the spatialresolution (depending on the wavelength and the number of openings ofthe detection optical system, for example, 0.7 to 0.9 μm at a wavelengthof 266 nm) of the detection optical system, the detection signals ofneighboring dots do not overlap with each other as shown in FIG. 9, andthe detection intensities of individual dots can be measured with highaccuracy.

The detection signals of the neighboring dots do not overlap with eachother ideally as described above, but because a bottom of a point imagedistribution function of the detection optical system overlaps with theadjacent dots, the placement of the adjacent dots may affect thedetection signals of the individual dots. During the actual adjustment,the spatial resolution of the detection optical system is low in thedefocused state, as a result of which the scattered light of a certaindot may interfere with and affect the scattered light of the close dot.Since a way of the influence of interference depends on the array of thedots, in the case where the array of the dots is asymmetrical, there isa risk that a difference in the adjustment state is present between theleft oblique detection optical system 170 b and the right obliquedetection optical system 170 c.

Meanwhile, the minimum repetition unit area 1902 according to thepresent embodiment has an array relationship in which the dot pattern inthe area from 0 to 10 dy and the dot pattern in the area from 10 dy to20 dy are mirror symmetric in the Y direction. For that reason, evenwhen the influence of the interference between the neighborhood dotsappears, the influence of the right and left asymmetry is canceled, anda difference can be prevented from occurring in adjustment state betweenthe left oblique detection optical system 170 b and the right obliquedetection optical system 170 c.

In the case of FIG. 9, in an adjustment state I, the center of theillumination area R_(I) is X=5 dx and the detection optical system isfocused, whereas in an adjustment state 2, the center of theillumination area RT is X=4 dx and the detection optical system is outof focus. The focusing of the detection optical system makes thewaveform of the dot detection signal sharper and increases the peakintensity. This can be discriminated because the maximum intensity ofthe dot detection signal (portions indicated by circles in FIG. 9) has arelationship of the adjustment state 1>the adjustment state 2.

If the interval dx of the dot array in the X direction is equal to orgreater than the width of the illumination area R_(I) or if the signalof the isolated dot is used as an adjustment reference, it is difficultto discriminate whether an increase or decrease in the peak intensity ofthe dot is caused by defocus of the detection optical system or causedby a change in relative position of the dot to the illumination areaR_(I) in the X direction. This makes it difficult to adjust the focus ofthe detection optical system with high accuracy.

On the other hand, in the dot pattern area 613 according to the presentembodiment, since the dot pattern array is sufficiently small in in theinterval dx in the X direction, the detection optical system can beadjusted with high accuracy without being affected by the positionvariation of the illumination area R_(I).

There are cases in which individual dot detection signals are not stablebecause the peak intensity is varied due to a slight variation in noiseof the sensor or the imaging state of the detection optical system.However, the dots closest to the center position of the illuminationarea R_(I) are present at 2M locations in the dot pattern area 613.Therefore, when, for example, an average value of the dot signalintensities at M′ (M′ is 2 or more and 2M or less) locations of thehigher dot signal intensity is set as an evaluation value, even if thepeak intensity of the individual dot signals is varied, the stableadjustment result can be obtained with a reduction in the influence ofthe variation in the peak intensity.

FIG. 10 shows an adjustment procedure of the illumination optical systemand the detection optical system using the pattern chip 191. In thisexample, an adjustment procedure of the oblique illumination opticalsystem and the detection optical system is shown. However, the sameprocedure can be performed for adjustment also in the combination of thevertical illumination optical system and the detection optical system.The respective steps in FIG. 10 show the details of the adjustment to becarried out at each stage, the pattern area used for the measurement,and the detection optical system for obtaining the detection signal. Thesequence will be described in order below. A sequence of processing isexecuted by the overall control unit 301.

First, the pattern chip 191 is moved by the stage 152 and placed in theillumination area R_(I) of the illumination optical system (that is, theposition to be inspected by the detection optical system) (Step S100).Next, the focal, point of the vertical detection optical system 170 a isadjusted with the use of a signal obtained by detecting the L & Spattern area 612 with the vertical detection optical system 170 a (StepS101). Next, the position of the illumination area R_(I) in the Xdirection with the illumination optical system 112 is adjusted with theuse of the signal obtained by detecting the L & S pattern area 612 bythe vertical detection optical system 170 a (Step S102). Subsequently,the focus of the illumination light by the oblique illumination opticalsystem 112 is adjusted with the use of a signal obtained by detectingthe L & S pattern area 612 with the vertical detection optical system170 a (Step S103).

Further, the positions of the detectors (106 b, 106 c) of the obliquedetection optical systems (170 b, 170 c) in the X direction are adjustedwith the use of a signal obtained by detecting the dot pattern area 613with the oblique detection optical systems (170 b, 170 c) (Step S104).Next, the focuses (that is, the z direction position of the detectors106 b and 106 c) of the oblique detection optical systems (170 b, 170 c)are adjusted with the use of a signal obtained by detecting the dotpattern area 613 with the oblique detection optical systems (170 b, 170c) (Step S105). Subsequently, the positions of the detectors (106 b, 106c) of the oblique detection optical systems (170 b, 170 c) in the Ydirection are adjusted with the use of a signal obtained by detectingthe dot one-row pattern area 611 with the oblique detection opticalsystems (170 b, 170 c) (Step S106).

Thereafter, the power measurement and adjustment of the illuminationlight are performed with the use of a signal, obtained by detecting theL & S pattern area 612 with the vertical detection optical system 170 a(Step S107). Next, optical magnifications of the detection opticalsystems (170 a, 170 b, 170 c) are measured with the use of a signalobtained by detecting the dot one-row pattern area 611 with thedetection optical systems (170 a, 170 b, 170 c) (Step S108). Thereafter,the inspection target substrate 2 is moved to the illumination areaR_(I) (Step S109).

In order to adjust the position and focus of the illumination light, thedetection optical system is required to be in focus. For that reason,the focus adjustment (Step S101) of the detection optical system isfirst performed as described above. The oblique detection optical systemhas the optical axis inclined with respect to the pattern chip 191 andis in focus only at a specific X direction position. For that reason,the focus of the vertical detection optical system is adjusted and usedfor adjusting the state of the illumination light. The verticaldetection optical system enables the detection of the pattern signals ofboth the L & S pattern area 612 and the dot pattern area 613. However,when the L & S pattern area 612 is used, there is advantageous in thatthe signal processing for extracting the dots located in the vicinity ofthe center of the illumination area R_(I) as described in FIG. 9 is notrequired.

The two-dimensional detector 109 is fixed at a designed image planeposition by the objective lens 102 a and the Imaging lens 105 a. The Zposition of the pattern chip 191 is adjusted according to the detectionsignal of the L & S pattern area 612 with the two-dimensional detector109 so that an intensity change in the Y direction comparable to an edgeof the line pattern becomes clearer, to thereby adjust the focus of thevertical detection optical system 170 a. Note that the Z position of thetwo-dimensional detector 109 and the Z position of the detector 106 a inconjunction with the Z position the two-dimensional detector 109 may beadjusted. With execution of Step S101, the Z position of the patternchip 191 is fixed to a position where the vertical detection opticalsystem 170 a is in focus.

In Step S102, the X position of the illumination area R_(I) is adjustedby the optical axis adjustment with the mirror unit 1101 so as to be setto a position at which the signal of the detector 106 a is maximized. InStep S103, the stage 1103 causes the oblique illumination optical system112 to move in the optical axis direction to adjust the focus so thatthe width of the illumination area R_(I) measured by the two-dimensionaldetector 109 becomes equal to or less than a predetermined va1ue.

A state in which the illumination area R_(I) by the illumination opticalsystem coincides with the detection visual field of the detectionoptical system (the X direction positions of the detectors 106 a, 106 b,and 106 c) and the respective optical systems are in focus in theillumination area RT is realized in Steps S100 to S109 described above.

In that state, adjustment parameters such as the height measurementvalues of the inspection target substrate 2 by the AF illuminationsystem 181 and the AF light receiving system 182, the height 2 settingvalue of the stage 152, the setting value of the adjustment mechanism(the mirror unit 1101, the stage 1103) of the oblique illuminationoptical system, the position setting values of the detectors 106 a, 106b, and 106 c, an adjustment completion time, the environmentalconditions at that time (a temperature, an atmospheric pressure and soon in the device internal space 2001) are recorded, and input to andsaved in the overall control unit 301.

FIG. 11 shows an inspection procedure to be executed in the defectinspection device 1000. The processing is executed by the signalprocessing unit 200 and the overall control unit 301. First, aninspection object (Inspection target substrate 2) is loaded into thedevice, and installs on the stage 152 (Step S702). Next, the inspectionconditions are set (Step S703). The inspection conditions include theillumination condition (for example, illumination angle: obliquedirection/vertical direction/both of oblique direction and verticaldirection) and the detection conditions (for example, each of thevertical detection optical system, the left oblique detection opticalsystem, and the right oblique detection system is used or not). Next,the illumination optical system and the detection optical system areadjusted and set (Steps S704 to S706, Step S710).

The target of adjustment and setting is the illumination optical systemand the detection optical system selected to be used in Step S703.First, an elapsed time since the last adjustment of the target opticalsystem is obtained, and it is determined whether or not a predeterminedperiod of time during which the state can be maintained after completionof the adjustment (Step S704). If the predetermined period of time haselapsed, the process proceeds to Step S710. If the predetermined timehas not elapsed, it is determined whether or not a change in theenvironmental conditions after the previous adjustment (a temperaturechange, an atmospheric pressure change, and so on in the device internalspace 2001) exceeds a predetermined threshold value (Step S705). If thechange exceeds a threshold, the process proceeds to Step S710. If notexceeding, the illumination optical system and the detection opticalsystem are set based on the adjustment parameters saved at the previousadjustment (Step S706). Next, the inspection is executed (Step S707),the inspection results are saved and displayed (Step S708), and theinspection is terminated (Step S709).

If any one of the determinations in Steps S704 and S705 is Yes, theadjustment of the optical system using the pattern chip is performed andthe adjustment parameter is updated. If a negative determination is madein neither Step S704 nor Step S705, the optical system is set with theuse of the adjustment parameters obtained by the adjustment using thepattern chip 191 at the time of inspection before a previous time.

According to the above method, when the adjustment state is deviated dueto the lapse of time or a change in environmental condi tions, resultingin a possibility that the original inspection performance cannot beobtained, the adjustment using the pattern chip 191 is performed, andthe inspection can be performed in a sufficiently adjusted state. Theadjustment using the pattern chip 191 is omitted in the case where it isexpected that the deviation of the adjustment state after the previousadjustment time is small enough not to cause any problem. This makes itpossible to avoid taking time for adjustment more than necessary andincrease the throughput of inspection.

(2) Second Embodiment

FIG. 12 shows an example of a dot array of a minimum repetition unitarea 1902 configuring a dot pattern area 613 of a pattern chip 191 usedin a second embodiment. The configuration is the same as that in thefirst embodiment except for the configuration of the pattern chip 191.The pattern chip 191 according to the present embodiment is different inthe configuration of the dot pattern area 613 from that in the firstembodiment.

The structure of individual dots 1903 configuring a minimum repetitionunit area 1902, an interval dy of the dots 1903 in the Y direction, andan interval dx in the X direction are the same as those in the firstembodiment. In other words, the interval dx of the dots 1903 in the Xdirection within a range of the minimum repetition unit area 1902 issufficiently smaller than a width (for example, 0.8 μm) of theillumination area R_(I), the interval dy of the dots 1903 in the Ydirection and an interval between the closest dots are larger than 1 μmand larger than a spatial resolution of the detection optical system(depending on a wavelength and the number of openings of the detectionoptical system, for example, 0.7 to 0.9 μm at a wavelength of 266 nm).The dots 1903 in the minimum repetition unit area 1902 are all differentin the positions in the Y direction.

After satisfying the above conditions of the dot intervals, the dots1903 are randomly arrayed at random in the minimum repetition unit area1902. The term “random” as referred to the present specification meansthat there is no specific directionality or no specific correlationdistance.

Since the dot array satisfying the above conditions has no specificdirectivity in the scattered light distribution and no deviationcorresponding to the specific directionality, there is an advantage thatthere is little difference in adjustment state of the right and leftoblique detection optical systems. Further, as compared with the dotpattern area 613 according to the first embodiment, although dx and dyare; common to the first and second embodiments, since there is no needto provide a mirror image symmetric pattern for canceling the influenceof the right and left asymmetry, the length 1 y of the minimumrepetition unit area 1902Y in the Y direction can be reduced (abouthalf) and the space efficiency is high, which is advantageous.

(3) Third Embodiment

The present embodiment is also the same as the first embodiment exceptfor the configuration of the pattern chip 191. FIG. 13 shows a dot arrayexample of a minimum repetition unit area 1902 configuring a dot patternarea 613 of a pattern chip 191 used in the third embodiment. The patternchip 191 according to the present embodiment is different in theconfiguration of the dot pattern area 613 from that of the first andsecond embodiments, except that the structure of each dot 1903 is commonto that of the first embodiment

In the present embodiment, there ere two dots 1903 in the minimumrepetition unit area 1902. The present embodiment employs a structure inwhich the minimum repetition unit area 1902 is repeatedly arrayed in twodimensions in the X and Y directions. In this situation, the dots 1903are arrayed so that K-fch order diffracted light of the diffractionpattern generated by the oblique illumination light enters the centersof the openings 102B and 102C of the. oblique detection optical system.

The minimum repetition unit area 1902 is an oblique lattice obtained byrotating an orientation by ϕ relative to an XY lattice (a lattice inwhich each side is parallel to the X direction and the Y direction), andin the above array, an interval of the dots 1903 in the X direction toan adjacent lattice aligned in the Y direction is dx. As an example,Ix=1.4 μm, 1 y=1.5 μm, ϕ=4 degrees, and dx=0.1 μm are met under thecondition that; an K=5th order diffracted light is incident in thevicinity of the center of opening of the oblique detection opticalsystem at the illumination wavelength 266 nm, and dy1 and dy2 areapproximately 0.8 μm. The minimum interval d between the dots is 1.0 μmand longer than the spatial resolution of the detection optical system(depending on the wavelength and the number of openings in the detectionoptical system, for example, 0.7 to 0.9 μm at a wavelength of 266 nm),and therefore overlapping of the signals does not occur between theadjacent dots.

As in the first embodiment, since dx is sufficiently smaller than thewidth of the illumination area R_(I), one of the dots 1903 repeated inthe Y direction is positioned in the vicinity cf the center of theillumination area R_(I).

FIG. 14 shows a positional relationship between the diffracted lightgenerated from the dot pattern area 613 due to the oblique, illuminationlight and the opening of the detection optical system. The pattern ofthe diffracted light from the dot pattern area 613 is obtained byFourier transform of the dot array in the dot pattern area 613 centeredon a position (0-th order diffracted light 1951) of the regularlyreflected light (0-th order diffracted light) of the illumination light.With the dot array under the above conditions, fifth order diffractedlights 1952 b and 1952 c are incident on the vicinity of the center ofthe openings 102B and 102C, respectively. The elliptical shape of thediffracted light which is elongated in the X direction in FIG. 14corresponds to a convergence angle of the illumination light in the Xdirection and the refracted light has an angular spread in the Xdirection.

The actual scattering pattern is closer to a distribution obtained byfurther convolving the diffracted light (scattered light) distributionof the individual dots shown in FIG. 7 with respect to the diffractedlight pattern of FIG. 14. Therefore, with the fifth order diffractedlight as the center, the spread diffracted light (scattered light) distribution is incident on the vicinity of the center of the obliquedetection optical system, thereby being capable of obtaining the dotdetection signal with a sufficient intensity for the oblique detectionoptical systems (170 b, 170 c).

(4) Other Embodiments

The present invention is not limited to the embodiments described above,but the present invention includes various modifications. For example,the above-described embodiments are described in detail for clarifyingthe present invention and not always limited to the provision of all theconfigurations described above. Further, a part of one embodimentconfiguration can be replaced with another embodiment configuration, andthe configuration of one embodiment can be added with the configurationof another embodiment. Also, in a part of the respective embodimentconfigurations, another embodiment configuration can be added, deleted,or replaced.

Control lines and information lines shown are considered to be necessaryfor description. All control lines and information lines are notnecessarily required for: products. It may be considered that almost allof the components are interconnected actually.

LIST OF REFERENCE SIGNS

-   101 . . . light source unit-   102 . . . objective lens,-   103 . . . objective pupil optical unit,-   104 . . . polarizer,-   105 . . . imaging lens,-   106 . . . detector,-   108 . . . mirror,-   109 . . . two-dimensional detector,-   110 . . . mirror,-   111 . . . TTL illumination optical system,-   112 . . . oblique illumination optical system,-   113 . . . mirror,-   151 . . . stage drive unit,-   152 . . . X-Y-Z-θ stage,-   170 a . . . vertical detection optical system,-   170 b . . . right oblique detection optical system,-   170 c . . . left oblique detection optical system,-   191 . . . pattern chip,-   200 . . . signal processing unit;,-   301 . . . overall control unit,-   302 . . . display unit,-   303 . . . arithmetic unit,-   304 . . . storage unit,-   601 . . . pattern area,-   602 . . . small pattern area,-   611 . . . one alignment pattern area,-   612 . . . line and space pattern area,-   613 . . . dot pattern area,-   1902 . . . minimum, repetitive unit area,-   1903 . . . dot

1. A defect inspection device comprising: a table unit on which a sampleto be inspected and a pattern chip are placed; an illumination lightirradiation unit that irradiates a surface of the sample or a surface ofthe pattern chip with an illumination light shaped to extend in a firstdirection; a detection optical unit that detects a diffracted light anda scattered light generated from the surface of the sample or thesurface of the pattern chip by the illumination light using a detectionoptical system having an objective lens and an image sensor; and asignal processing unit that adjusts a focus of the detection opticalsystem and detects a defect on the surface of the sample based on asignal output from the detection optical unit, wherein the pattern chiphas a dot pattern area in which a plurality of dots are arrayed in aplurality of rows and a plurality of columns, a minimum interval betweenthe dots corresponding to the lines aligned in the first direction amongthe plurality of dots arrayed in the dot pattern area in a seconddirection orthogonal to the first direction is smaller than a width ofthe illumination light, and a minimum interval between the plurality ofdots arrayed in the dot pattern area is larger than a resolution of thedetection optical system.
 2. The defect inspection device according toclaim 1, wherein a shape of the dots is round.
 3. The defect inspectiondevice according to claim 1, wherein a diameter of the dots is smallerthan a resolution of the detection optical system.
 4. The defectinspection device according to claim 1, wherein a minimum intervalbetween the plurality of dots appearing on the same row among the dotsconfiguring the dot pattern area is larger than a width of theillumination light.
 5. The defect inspection device according to claim1, wherein the dots have a concave pattern.
 6. The defect inspectiondevice according to claim 1, wherein the pattern chip further includes aone-row dot pattern configured by a pattern in which the dots arealigned in one row, and the dot pattern area and the one-row dot patternare arranged in different areas in the first direction.
 7. A patternchip that is placed on a table unit of a defect inspection device andirradiated with an illumination light shaped to extend in a firstdirection, wherein the pattern chip lias a dot pattern area in which aplurality of dots are arrayed in a plurality of rows and a plurality ofcolumns, a minimum interval between the dots corresponding to the linesaligned in the first direction among the plurality of dots arrayed inthe dot pattern area in a second direction orthogonal to the firstdirection is smaller than a width of the illumination light, and aminimum interval between the plurality of dots arrayed in the dotpattern area is larger than a resolution of the detection opticalsystem.
 8. The pattern chip according to claim 7, wherein a shape of thedots is round.
 9. The pattern chip according to claim 7, wherein adiameter of the dots is smaller than a resolution of the detectionoptical system.
 10. The pattern chip according to claim 7, wherein aminimum interval between the plurality of dots appearing on the same rowamong the dots conf iguring the dot pattern area is larger than a widthof the illumination light.
 11. The pattern chip according to claim 7,wherein the dots have a concave pattern.
 12. A method of inspecting adefect comprising: a step of irradiating a surface of the sample or asurface of the pattern chip with an illumination light shaped to extendin a first direction; a step of detecting a diffracted light and ascattered light generated from the surface of the sample or the surfaceof the pattern chip by irradiation of the illumination light using adetection optical system having an objective lens and an image sensor; astep of adjusting a focus of the detection optical system based ondetection signals corresponding to the refracted light and the scatteredlight generated from the surface of the pattern chip; and a step ofdetecting a defect on the surface of the sample based on detectionsignals corresponding to the refracted light and the scattered lightgenerated from the surface of the sample, wherein the pattern chip has adot pattern area in which a plurality of dots are arrayed in a pluralityof rows and a plurality of columns, a minimum interval between the dotscorresponding to the lines aligned in the first direction among theplurality of dots arrayed in the dot pattern area i.n a second directionorthogonal to the first direction is smaller than a width of theillumination light, and a minimum interval between the plurality of dotsarrayed in the dot pattern area is larger than a resolution of thedetection optical system.
 13. The method of inspecting a defectaccording to claim 12, wherein a shape of the dots is round.
 14. Themethod of inspecting a defect according to claim 12, wherein a diameterof the dots is smaller than a resolution of the detection opticalsystem.
 15. The defect inspection device according to claim 12, whereina minimum interval between the plurality of dots appearing on the samerow among the dots configuring the dot pattern area is larger than awidth of the illumination light.